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package fr.annuaireComp.facades;

import java.util.List;
import java.util.Map;
import javax.persistence.EntityManager;
import javax.persistence.Tuple;
import javax.persistence.criteria.CriteriaBuilder;
import javax.persistence.criteria.CriteriaQuery;
import javax.persistence.criteria.Predicate;
import javax.persistence.criteria.Root;
import javax.transaction.Transaction;

/**
 *
 * @author MiniK
 */
public abstract class AbstractFacade<T> {
    private Class<T> entityClass;

    public AbstractFacade(Class<T> entityClass) {
        this.entityClass = entityClass;
    }

    protected abstract EntityManager getEntityManager();

    public void create(T entity) {
        getEntityManager().persist(entity);
    }

    public void edit(T entity) {
        getEntityManager().merge(entity);
    }

    public void remove(T entity) {
        getEntityManager().remove(getEntityManager().merge(entity));
    }

    public void refresh(T entity)
    {
        getEntityManager().refresh(entity);
    }
    public T find(Object id) {
        return  getEntityManager().find(entityClass, id);
        //  return getEntityManager().refresh(getEntityManager().find(entityClass, id));
    }
    
    public List<T> findBy(Map<String, Object> params) 
    {
        CriteriaBuilder cb = getEntityManager().getCriteriaBuilder();           
        CriteriaQuery cq = cb.createQuery();     
        Root<T> r = cq.from(entityClass);

        Predicate p= cb.conjunction();
        for (Map.Entry<String, Object> param: params.entrySet())
            p = cb.and(p, cb.equal(r.get(param.getKey()), param.getValue()));

        cq.select(r).where(p);

       return getEntityManager().createQuery(cq).getResultList();
    
    }

    public List<T> findAll() {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        cq.select(cq.from(entityClass));
        return getEntityManager().createQuery(cq).getResultList();
    }

    public List<T> findRange(int[] range) {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        cq.select(cq.from(entityClass));
        javax.persistence.Query q = getEntityManager().createQuery(cq);
        q.setMaxResults(range[1] - range[0]);
        q.setFirstResult(range[0]);
        return q.getResultList();
    }

    public int count() {
        javax.persistence.criteria.CriteriaQuery cq = getEntityManager().getCriteriaBuilder().createQuery();
        javax.persistence.criteria.Root<T> rt = cq.from(entityClass);
        cq.select(getEntityManager().getCriteriaBuilder().count(rt));
        javax.persistence.Query q = getEntityManager().createQuery(cq);
        return ((Long) q.getSingleResult()).intValue();
    }
    
}
